多年生温带禾本科植物的夏季休眠
Summer dormancy in perennial temperate grasses.
作者信息
Volaire Florence, Norton Mark
机构信息
Institut National de Recherche Agronomique, INRA UMR SYSTEM, 2 place Viala, Montpellier, France.
出版信息
Ann Bot. 2006 Nov;98(5):927-33. doi: 10.1093/aob/mcl195. Epub 2006 Oct 6.
BACKGROUND AND AIMS
Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temperate grasses originating from the Mediterranean Basin, and presents a unified terminology to describe this trait.
SCOPE
Under severe drought, it is difficult to separate the responses by which plants avoid and tolerate dehydration from those associated with the expression of summer dormancy. Consequently, this type of endogenous (endo-) dormancy can be tested only in plants that are not subjected to moisture deficit. Summer dormancy can be defined by four criteria, one of which is considered optional: (1) reduction or cessation of leaf production and expansion; (2) senescence of mature foliage; (3) dehydration of surviving organs; and (4, optional) formation of resting organs. The proposed terminology recognizes two levels of summer dormancy: (a) complete dormancy, when cessation of growth is associated with full senescence of foliage and induced dehydration of leaf bases; and (b) incomplete dormancy, when leaf growth is partially inhibited and is associated with moderate levels of foliage senescence. Summer dormancy is expressed under increasing photoperiod and temperature. It is under hormonal control and usually associated with flowering and a reduction in metabolic activity in meristematic tissues. Dehydration tolerance and dormancy are independent phenomena and differ from the adaptations of resurrection plants.
CONCLUSIONS
Summer dormancy has been correlated with superior survival after severe and repeated summer drought in a large range of perennial grasses. In the face of increasing aridity, this trait could be used in the development of cultivars that are able to meet agronomic and environmental goals. It is therefore important to have a better understanding of the genetic and environmental control of summer dormancy.
背景与目的
休眠现象在经历严冬条件的植物中已得到广泛研究，但在必须度过夏季干旱的多年生草本植物中研究较少。本文综述了源自地中海盆地的本地和栽培多年生温带禾本科植物夏季休眠的现有知识，并提出了一个统一的术语来描述这一特性。
范围
在严重干旱条件下，很难区分植物避免和耐受脱水的反应与那些与夏季休眠表达相关的反应。因此，这种内源性（endo-）休眠只能在未遭受水分亏缺的植物中进行测试。夏季休眠可由四个标准定义，其中一个被认为是可选的：（1）叶片产生和扩展减少或停止；（2）成熟叶片衰老；（3）存活器官脱水；以及（4，可选）休眠器官的形成。所提出的术语识别出夏季休眠的两个水平：（a）完全休眠，即生长停止与叶片完全衰老和叶基部诱导脱水相关；（b）不完全休眠，即叶片生长受到部分抑制并与中等水平的叶片衰老相关。夏季休眠在光周期和温度增加时表达。它受激素控制，通常与开花以及分生组织中代谢活性的降低相关。脱水耐受性和休眠是独立的现象，不同于复苏植物的适应性。
结论
在许多多年生禾本科植物中，夏季休眠与在严重且反复的夏季干旱后具有更高的存活率相关。面对日益干旱的情况，这一特性可用于培育能够实现农艺和环境目标的品种。因此，更好地理解夏季休眠的遗传和环境控制非常重要。
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